This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
it depends on the application server that is being used. you can check on the documentation of the application server in which you are deploying your code. I know weblogic has its entry in the weblogic.xml for this.
so, check with your application server specifications or tell us the application server.